Aliphatic compounds containing oxygen atoms

ABSTRACT

Oligomers of tetrafluoroethylene (C2F4)n where n is 4 to 6 react at 25*-100*C with aqueous solutions of sodium or potassium hydroxides to give novel oxygen-containing derivatives in which the oxygen is located in hydroxyl, carbonyl or carboxyl groups. With 5-15% by weight solutions of the hydroxides the tetramer yields a tertiary alcohol; the pentamer yields the ketone (C2F5)2(CF3)C.CH2COCF3, and hexamer yields a mixture of the ketone (C4F9)(C2F5)(CF3)C.CH2COCF3 and the ketene (C2F5)2(CF3)C.C(CO).CF(CF3)(C2F5). With 30-60% solutions the pentamer yields the acid (C2F5)2(CF3)C.CH2COOH. These oligomer derivatives are intermediates for making surfactants and oleophobic compounds for application to textiles and leather.

1451 Dec. 2, 1975 ALIPI-IATIC COMPOUNDS CONTAINING OXYGEN ATOMS [75] Inventor: Harold Crosbie Fielding, Northwich,

England [73] Assignee: Imperial Chemical Industries Limited, London, England [22] Filed: Dec. 30, 1970 [21] Appl. No.: 102,918

Related U.S. Application Data [62] Division of Ser. No. 699,049, Jan. 19, 1968, Pat. No.

[30] Foreign Application Priority Data Jan. 23, 1967 United Kingdom 3361/67 [52] U.S. Cl. 260/593 H [51] Int. Cl. C07c 49/04 [58] Field of Search 260/593 R, 593 H, 585.5, 260/653.1

[56] References Cited UNITED STATES PATENTS 2,802,034 8/1957 Hauptschein 260/593 H 3,029,252 4/1962 Simmons 260/593 3.091.643 5/1963 Wiley 260/595 FOREIGN PATENTS OR APPLICATIONS l,082,l27 9/1967 United Kingdom 260/653 R Primary E.\'aminerBernard Helfin Assistant Examiner-James H. Reamer Attorney, Agent, or FirmCushman, Darby & Cushman [57] ABSTRACT Oligomers of tetrafluoroethylene (C F where n is 4 to 6 react at 25100C with aqueous solutions of sodium or potassium hydroxides to give novel oxygencontaining derivatives in which the oxygen is located in hydroxyl, carbonyl or carboxyl groups. With 5-15% by weight solutions of the hydroxides the tetramer yields a tertiary alcohol; the pentamer yields the ketone (C F (CF )C.CH COCF and hexamer yields a mixture of the ketone (C,,F )(C F )(CF )C.CH COCF and the ketene (C F5) (CF )C.C(CO).CF(CF )(C F With 30-60% solutions the pentamer yields the acid (C F (CF )C.CH COOH. These oligomer derivatives are intermediates for making surfactants and oleophobic compounds for application to textiles and leather.

3 Claims, N0 Drawings ALIPHATIC COMPOUNDS CONTAINING OXYGE ATOMS This is a division of application Ser. No. 699,049, filed 1/19/68, now US. Pat. No. 3,632,641.

none directly pertinent'known; some highly fluorinated long-chain aliphatic compounds are'known to possess oleophobic properties.

SUMMARY OF THE INVENTION Preparation of oxygen-containing derivatives of'tetrafluoroethylene oligomers, in which. the oxygen is ide and subsequently fractionating the reaction products to separate said ketene and ketone.

The termsdilute and concentrated-in relation to the aqueous solutions of alkali metal hydroxides are such that the preferredstrengthsof the dilute solutions are from Ste 115% and ofthe concentrated solutions 30to 60%by weight. Minor. amounts of the perfluoroalkyl acetic acid can be produced. together with major amounts of the perfluoroalkylmethylatrifluoromethyl ketone even when dilute solutionsof the hydroxides are reacted with the pentamen biit when concentrated solutions are used only the perfluoroalk'ylacetic acid is combined in hydroxyl, carbonyl or carboxyl groups, by

reacting oligomers with aqueous solutions of alkali metal hydroxides at --1OOC.

This invention relates to highly fluorinated compounds whose molecules contain oxygen atoms particularly to the preparation from oligomers of tetrafluoroethylene of highly fluorinated aliphatic acids, ketones, ketenes and alcohols. g

In this specification the termoligomer means an internally unsaturated, branched-chain low polymer of tetrafluoroethylene having the empirical formula (C F where n is an integer from 4 to about 12, particularly 4 to 6. I

We have found that oligomers of tetrafluoroethylene react with aqueous solutions of alkali metal hydroxides. The initial reaction in all cases appears to be the replacement of a fluorine atom by a hydroxyl group to give an alcohol.-After this-further reactions can take place whose course is determined by thes'tructure of the oligomer and the -concentrationfl of the aqueous alkali metal hydroxide-solti tion,and they lead to the formation of highly fluorinatedaliphatic acids, ketones andketenes. When the oligomer is thetetramer the fur.- ther reactions follow a slightly different-courseand the main product is an alcohol. The p'entamer on the other hand gives an acid and a ketone whilst hexamer. gives a ketene and a ketone.

In its general form the invention thus provides a process for making from tetrafluoroethylene oligomers derivatives whose molecules contain oxygen atoms combined in groups selected from hydroxyl, carbonyl and carboxyl groups, comprising reacting an oligomer with an aqueous solution of an alkali metal hydroxide.

In one particular form the invention provides a pro-' cess for making from tetrafluoroethylene pentamer the perfluoroalkyl acetic acid R,CH COOH and the perlluoroalkylmethyl trifluoromethyl ketone R CH COCF where R; represents the perfluoroalkyl group (C F (CF )C, comprising reacting tetrafluoroethylene pentamer with respectively concentrated and dilute aqueous solutions of an alkali metal hydroxide.

In another particular form the inventionprovides a process for making from tetrafluoroethylene hexamer the perfluoroalkyl ketene (R,)(R;)C=CO and the perfluoroalkylmethyl trifluoromethyl ketone R ,Cl-I COCF where R,, R; and R represent respec- .f

(C2F5)2(CF3)C,

tively the perfluoroalkyl groups found in the reaction products.- The ketone can in fact be'changed into the acid by treating it with concentrated solutions of the hydroxides. The amount'of alkali metal hydroxiderequired' for the reaction is usually from four to ten moles per mole o'f oligomer.

The reactions proceed satisfactorily-at moderately elevated temperatures; preferably from 25C to 1009C. They are exothermic and little applied heat is required; After the initially vigorous reaction has subsided it is convenient to reflux the reaction 'mixturefor a period. If a small proportion of an organic solvent ispresent, for example about 10% by volume of -the=reaction mixture, the exothermic reaction tends to initiate more readily. Suitable organic solvents incl'ude dime'thyl ethers of ethylene glycol and of diethylene glycol and t-butanol. I V l The ketene and ketone are separated from the products of the reaction between hexamer and alkali metal hydroxide by fractional distillation. The ketene is collected in the fraction boiling at l55-l 62C and the ketone in the fraction boiling at 162Cl 80C, ketene and ketone are then isolated from theirr espectivefractions by gas-liquid chromatography.

The tetrafluoroethylene oligomer d e ri L of the invention are useful intermediates, particularly" in the preparation of surfactants, of oleophobic compounds for application to textilesaiid'to other surfaces. For example i the per''fluoroal kylaceti c 'acid C F (CF )C.C l-I CO OH can be esterified with ethan01 to give an ethyl este rror converted into water-soluble salts whose aqueous solutions have low surface-tensions and are useful in aqueous emulsion polymerisations, or reacted with acetylene to give vinylester that can beipolymerised to give fluorocarbon polymers soluble in solvents such as benzotriflubri'de and 1,1,2-trifluoro-1,2,2-trich1oroethane to give solutions that impart oleophobic and hydrophobic properties to textiles and leather when applied thereto. The vinyl ester can also be copo ymerised with polymerisable monomers, for example butyl methacrylate, to give copolymers soluble in chlorinated solvents and possessing film-forming properties.

The perfluoroalkylmethyl trifluoromethyl ketone, (C F (CF )C.CH COCF can be reduced to the corresponding secondary alcohol which can be esterified with acrylic acid to give an acrylate which has been polymerised to polymers soluble in fluorinated solvents .and possessing oleophobic and hydrophobic properties.

The secondary alcohol v can also be sulphonated to give a surfactant.

,1. The alcohol formed from the tetramerpanalytical data, for which are consistent-:with the formula (C F )(CF )CF and (C F'i,)(C F5)(CF )C, comprising/u, reacting tetrafluoroethylene hexamer mixed isomers? (Cgwith dilute solutions of an alkali metal hydrox-.

'(F )C( Ol-I)CH=CF that is to say a tertiary alcohol", caribeacrylated to give-," after polymerisation,

--oleophbi c a nd hydrophobic polymers, and can be sulphonated to give 'a surfactant. 5 l

3 4 The ketone formed from the hexamer is surprisingly stirred at 90C for l hours. and was then allowed to stable. as shown by its isolation from aqueous alkaline cool. A small lower layer (unreacted pentamer. 10 g.) solution. presumably owing to steric hindrance. With was separated, and the aqueous layer was then acidified ethanol it reacts to give the-ethyl ester of the correwith sulphuric acid. The lower layer which separated sponding acid. and it can react with hydroxyethyl meth- 5 was run off. dried over magnesium sulphate, and disacrylate to give a polymerisable monomer. The ketone tilled to give the ketone. b.pt. l27l 28C. The product formed from the hexamer is analogous to that formed (60 g.) gave a single peak on a gas-liquid chromatofrom the pcntamer and behaves as an intermediate in gram. and showed a strong carbonyl absorption at 5.6 the same types of reactions. microns and very strong C-F absorption at 8.0-8.5 microns. Infra-red spectra, elemental analysis, mass-spec- EXAMPLE 1 tra and nuclear magnetic resonance measurements Tetrafluoroethylene pcntamer (50 g.) was added were consistent with the product being the ketone slowly to a stirred solution of potassium hydroxide (40 (C. ,F,-,) (CF,-,)C.CH COCF g.) in water (40 mls.) and dimethyl ether of diethylene glycol (5 mls.). The vigorous exothermic reaction was EXAMPLE 4 controlled by the rate of addition of pentamer. When Sodium hydroxide (200 g.) in water (2 litres) was all the pcntamer had been added, the still strongly alkaadded slowly to a vigorously stirred mixture of pentaline solution was heated under reflux for 1 hour. mer (500 g.) and dimethyl ether of diethylene glycol The reaction mixture was then cooled. acidified with mls) at 40C. The rate of addition of sodium hysulphuric acid. and extracted with ether. The ether exdroxide solution was adjusted to maintain a temperatract was dried and distilled to give the acid. b.pt. ture of about 45C with slight external cooling. After I 10C at 18 mm. Hg which solidified on standing (yield completion of the addition (3 hours) the reactants were 26.0 g. infra-red and mass-spectra and nuclear magstirred at 45C for a further 30 minutes. nctic resonance spectra were consistent with the prod- The reaction mixture was cooled, and the lower layer uct being the perfluoroalkylacetic acid. (unreacted pcntamer 56 g.) was separated. Acidifi- (C- ,F ,(CF;,)C.CH COOH. cation of the aqueous layer with sulphuric acid gave o 5 OCOCF' b. t. EXAMPLE 2 340g of the ketone (C F, (CF,;)C CH p Found C. 25.69? H. 0.5%: F. 7l.2'/l by weight. Calculated for C,,H. -F,..O I C 251: H. 0.5%. F. 70.7% by weight.

Potassium hydroxide (l000 in water (i000 mls.)

was stirred at 80C in a S-Iitre flask fitted with a water 35 EXAMPLE 5 condenser. dropping funnel and internal thermometer. Sodium hydroxide (l6 g.) in water (160 mls.) was Tetrafluoroethylene pcntamer 1000 g.) was added added dropwise to a vigorously stirred mixture of tetraslowly at such a rate as to maintain steady reflux withmer (40 g.) and dimethyl ether of diethylene glycol (4 out the application of external heat. When the addition 40 mls.) at room temperature. An exothermic reaction was complete, the mixture was stirred and heated began and the temperature rose to 35-40C. When all under reflux for 1V2 hours. On cooling to room temperthe alkali had been added, stirring was continued at ature. the potassium salt of the acid separated and was 40C for a further hour. after which the reaction mixfiltered off. The filtered salt was dissolved in hot water. ture was cooled. A lower layer (10 g.) of unchanged acidified with sulphuric acid and cooled in ice. The tetramer separated. The aqueous layer was acidified to acid separated out as a lower liquid layer which solidigive a lower layer. which was separated (20 g.). Distilfied and was filtered off. Recrystallisationfrom acetone lation of this layer gave a fraction b.pt. 79C, weight 8 gave 530 g. of the acid, (C. .F (CF )C.CH COOH), g.

Found C. 5.2% H. 1.171 F. 68.4% by weight Calculated for C F H C. 25.7% H. 0.7% F. 67.9% b\ weight m.pt. 57C. Infra-red absorption spectra, mass-spectra and nu- Found C. 25.2%: H. 0.9%: F. 65.2% by weight. Calculated for C,.H;.F, O C. 25.4%. H. 0.8%: F. 65.37: by weight.

clear magnetic resonance data were consistent with the EXAMPLE 3 structure Tetrafluoroethylene pcntamer (I00 g.) was added slowly to a stirred solution of sodium hydroxide (40 g.) in water (250 mls.) and dimethyl ether of diethylene OF? glycol (10 mls.). The exothermic reaction was controlled by the rate of addition of pentamer. When all the pcntamer had been added, the reaction mixture was A small amount of a fraction boiling at 83C was possibly the ketone EXAMPLE 6 Sodium hydroxide (64 g.) in water (640 mls.) was added slowly to a vigorously stirred mixture of hexamer (mixed isomers, 200 g.) and dimethyl ether of diethylene glycol l0 mls.) heated to 80C. On completion of the addition (2 hours) the reaction temperature was raised to 90C for a further 3 hours, after which the reaction mixture was allowed to cool. It was then acidified, and the lower layer separated. Fractionation of this layer 160 g.) gave some unchanged hexamer (isomers), together with a mixture of products.

The fraction b.pt. l55-l62C (100 g.) contained one main component which was separated by gas-liquid chromatography and characterised by infra-red absorption spectra mass-spectra and nuclear magnetic resonance data as the ketone The fraction b.pt. l62l80C g.) contained a further main component which was separated by gas- LII 6 liquid chromatography and characterised as the ketone 4 9)( 2 3)( F=;) 2 3- On refluxing the ketene 10 g.) with an excess of dry ethanol l0 mls.) the ketene peak in the infra-red absorption spectrum slowly disappeared (4.7a) to be replaced by an ester peak at 5.65 1.

Infra-red absorption spectra, mass-spectra and micro-analysis confirmed the product to be the ethyl ester 

1. A PROCESS FOR MAKING THE PERFLUOROALKYLMETHYL TRIFLUOROMETHYL KETONE, (C2F5)2(CF3)C.CH2COCF3, COMPRISING REACTING AT 25* TO 100*C. TETRAFLUOROETHYLENE PENTAMER WHICH IS INTERNAL UNSATURATED AND BRANCHED CHAIN AND HAS THE EMPERICAL FORMULA (C2F4)5 WITH AN AQUEOUS SOLUTION OF AN ALKALI METAL HYDROXIDE SELECTED FROM SODIUM HYDROXIDE AND POTASSIUM HYDROXIDE CONTAINING FROM 5 TO 15% BY WEIGHT OF THE ALKALI METAL HYDROXIDE.
 2. The perfluoroalkylmethyl trifluoromethyl ketone having the molecular formula (C2F5)2(CF3)C.CH2COCF3 and being a liquid boiling at 127*C-128*C under atmospheric pressure.
 3. The perfluoroalkylmethyl trifluoromethyl ketone having the molecular formula (C4F9)(C2F5)(CF3)C.CH2COCF3. 